What about a good Buddhist or Hindu? These people are very religious and just as sincere as you are. God will accept them, won't He? Is there only one way?
Sincerity is absolutely necessary in coming to God. The Bible condemns lying and dishonesty, but often mentions how vital it is to be sincere (note such passages as 1 Corinthians 5:8; 2 Corinthians 1:12; Ephesians 6:24; Philippians 1:10).
However, it is possible for someone to be sincere, but sincerely wrong. The Bible says there is a way that seems right unto a man, but the end of that way are the ways of death (Proverbs 16:25). A good biblical example of this is Saul of Tarsus, who, in all good conscience persecuted the church of God. Was he sincere? I think so. Was he wrong? By his own confession, he was (see 1 Timothy 1:13).
We regularly hear of a person foolishly pointing a gun at someone, sincerely believing it is empty. The gun discharges, and someone is killed. The person who pulled the trigger stands there in shock, saying, "I didn't know it was loaded." That person was 100% sincere in his desire not to harm anyone. But he was sincerely believing something untrue. Safety experts have a saying, "Loaded guns never seem to kill people; it's always empty guns that kill people." A sincere belief in a falsehood can be fatal.
The apostle Paul warns that practicing religion does not excuse anyone; in fact, it may multiply the religionist's guilt. Pagan religions have deliberately distorted and overthrown truth. They exchanged the truth of God for a lie (Romans 1:25).
Both Buddhism and Hinduism practice idolatry. The God of the Bible detests idolatry as an "abomination." It is a direct insult to the dignity of God. "Thou shalt have no other gods before Me. Thou shalt not make unto thee any graven image, or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth: Thou shalt not bow down thyself to them, nor serve them: for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate Me; and showing mercy unto thousands of them that love Me, and keep My commandments" (Exodus 20:3-6).
Joshua, the leader who brought the Jews into the land of Canaan, pled with them, "Now therefore fear the Lord, and serve Him in sincerity and in truth: and put away the gods which your fathers served on the other side of the flood, and in Egypt; and serve ye the Lord. And if it seem evil unto you to serve the Lord, choose you this day whom ye will serve; whether the gods which your fathers served that were on the other side of the flood, or the gods of the Amorites, in whose land ye dwell: but as for me and my house, we will serve the Lord" (Joshua 24:14-15).
Regardless of sincerity, a religious person who worships the wrong god has no advantage. The doors and the ignition switch to my car will only respond to one set of keys, and that is the way I want it. Likewise there is only one set of keys that unlocks heaven to guilty sinners, and those keys belong to the Lord Jesus Christ. God has not confused us with scores of options for how to get to heaven "to each his own," as long as you are sincere. Christ said, "Jesus said to him, 'I am the way, the truth, and the life. No one comes to the Father except through Me'" (John 14:6).
It is not your belief that provides salvation for you. It is the object of your belief that matters. For example, believing that someone will catch me if I jump from a burning building is only good if someone is actually willing, able, and available to catch me.
If you don't believe you need a Savior, any religion will probably do. But if you have discovered something fundamentally wrong within, and you realize you need a Savior, the list is very short--there is only one offered. His name is Jesus. No other religion has one (they essentially tell you to save yourself by your own efforts). "...Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead...Nor is there salvation in any other, for there is no other name under heaven given among men by which we must be saved" (Acts 4:10,:12).
Link to Uplook